1. Field of the Invention
The present invention relates to an image forming apparatus such as a digital copier, which generates an image based on image data which is stored in an image memory.
2. Discussion of the Background
A digital copier which has a scanner, an image memory and a printer is known. In this digital copier, the scanner scans documents, generates image data from the scanned documents, and stores the image data in the image memory. The printer prints an image on a recording medium (e.g., paper) according to the image data from the scanner or the image memory.
In digital copiers, editing functions are known. Known editing functions include an image rotating function and a combining function which prints two or more images from original documents onto a single recording medium. In the editing function, the scanner reads original documents and the image data from the scanner is stored into the image memory after processing according to the editing function. Then, after storing the image data, the printer prints the edited image on the recording medium according to the edited image data which is stored in the image memory after editing.
However, in this known digital copier, when using the editing function, it takes more time to make copies than compared with copies made without using the editing function because, when using the editing function, the image data is stored into the image memory once after editing, and after storing the image, the stored image is read out and printing is carried out.
Also, a book copying mode is known. The book copying mode is a mode for making copies of a book. In the book copying mode, the book is used as an original document which is set on a document glass. The book is spread open so that both pages are on the document glass, and an image of each page is printed on a different recording medium or on different sides of one recording medium. Hereinafter, when two pages of a book are copied sequentially, the layout of the pages will be called two "facing-pages".
When making one copy in the book copying mode, the scanner reads the image of a first page of two facing-pages and the printer prints the image of the first page according to the image data from the scanner. Next, the scanner reads the image of a second page of the two facing-pages and the printer prints the image of the second page according to the image data from the scanner on a different recording medium or on the opposite side of the recording medium on which was printed the first page of the two facing-pages.
In general, when making more than two copies of documents with this digital copier, the scanner reads a first original document, and the image data from the scanner is stored in the image memory. In parallel with this storing, the printer prints the image on the first recording medium according to the image data from scanner. After that, the printer prints second or subsequent copies according to the image data which is stored in the image memory. After making copies of a first original document, the operation of making copies of second or subsequent original documents is carried out as in case of the making copies of first document.
In the book copying mode, when making more than two copies of a book as original, the scanner reads the image of the first page of two-facing-pages and the image memory stores the image data from the scanner. In parallel with this storing step, the printer prints an image on the first recording medium according to the image data received from scanner. After that, the printer prints the image of the first page of the two facing-pages on a second or subsequent recording medium according to the image data which is stored in the image memory. After the first page of the two facing-pages has printed, the scanner reads the image of a second page of the two facing-pages, and the image data is stored. The image of the second page is printed in the same fashion that the first page of the two facing-pages was printed.
However, in this known digital copier, when making more than two copies of a book in the book copying mode, an operator must hold a book on the document glass while 1) reading the first page of two facing-pages, 2) printing a quantity specified by an operator, and 3) reading the second page of the two facing-pages.